升级Python stomp至8.0.1后遇SSL库未找到错误，求解决方案

问题背景 #

将Python stomp客户端从7.0.0版本升级至8.0.1版本后，连接队列时出现以下错误：

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/mpsmqutils/mqlistener.py", line 64, in connect_and_subscribe
    conn.set_ssl([(_host, _port)])
  File "/usr/local/lib/python3.8/site-packages/stomp/connect.py", line 68, in set_ssl
    self.transport.set_ssl(*args, **kwargs)
  File "/usr/local/lib/python3.8/site-packages/stomp/transport.py", line 859, in set_ssl
    raise Exception("SSL connection requested, but SSL library not found")
Exception: SSL connection requested, but SSL library not found

该错误来自stomp.py的transport.py文件中SSL检查逻辑，是版本更新时调整SSL依赖导致的。

核心问题 #

1. 客户端连接代码需要做哪些修改才能恢复正常？
2. 是否需要向set_ssl()传入额外参数？

现有连接代码 #

def connect_and_subscribe(conn, queue=_queue, sub_id=_sub_id):
    print(_hostname_prefix + "************************ MQUTILS MQLISTENER - CONNECT_AND_SUBSCRIBE *******************************")
    global _reconnect_attempts
    _reconnect_attempts = _reconnect_attempts + 1
    if _reconnect_attempts <= _max_attempts:
        # TODO: Retry timer with exponential backoff
        time.sleep(1)
        try:
            if not os.getenv('MQ_DISABLE_SSL'):
                if _failback_host and _failback_port:
                    conn.set_ssl([(_host, _port),(_failback_host, _failback_port)])
                else:
                    conn.set_ssl([(_host, _port)])
            if not conn.is_connected():
                conn.connect(_user, _password, headers={'client-id': _client_id}, wait=True)
                print(f'{_hostname_prefix}connect_and_subscribe connecting {queue} to with connection id {sub_id} reconnect attempts: {_reconnect_attempts}', flush=True)
            else:
                print(f'{_hostname_prefix}connect_and_subscibe already connected {queue} to with connection id {sub_id} reconnect attempts {_reconnect_attempts}', flush=True)
        except Exception as e:
            print(_hostname_prefix + 'Exception on disconnect. reconnecting...')
            print(_hostname_prefix + traceback.format_exc())
            connect_and_subscribe(conn)
        else:
            conn.subscribe(destination=queue, id=sub_id, ack='client-individual')
            _reconnect_attempts = 0
    else:
        print('{}Maximum reconnect attempts reached for this connection. reconnect attempts: {}'.format(_hostname_prefix, _reconnect_attempts), flush=True)

解决方案 #

问题1：代码修改要点 #

stomp.py 8.x版本后，SSL依赖不再默认包含在基础安装包中，需先安装额外的SSL依赖库：

• 执行安装命令：pip install stomp.py[ssl]

代码本身无需大幅修改，但要确保初始化连接时使用的是支持SSL的Transport类。新版本中，只要安装了ssl依赖，原有Connection类会自动启用SSL支持，无需手动替换。

问题2：是否需要额外参数 #

不需要向set_ssl()传入额外参数，原有的参数格式是正确的。但有两点需要注意：

• 必须先安装stomp.py[ssl]依赖，否则即使参数正确，依然会抛出SSL库未找到的错误。
• 如果需要自定义SSL配置（如指定加密协议、证书文件等），可以在set_ssl()中传入对应参数，示例：

  import ssl
  conn.set_ssl([(_host, _port)], ssl_version=ssl.PROTOCOL_TLSv1_2, cert_file="/path/to/cert.pem")
  

内容的提问来源于stack exchange，提问作者pengz